The present invention relates to a method for manufacturing a microlens substrate, and to a microlens substrate, an opposing substrate for a liquid crystal panel, a liquid crystal panel, and a projection display apparatus.
Hitherto, a projection display apparatus for projecting images on a screen has been known. In a projection display apparatus of this type, liquid crystal panels (liquid crystal optical shutters) are generally used for forming images.
A liquid crystal panel having such a configuration is known, which is provided with a number of minute microlenses in positions, each corresponding to a pixel of the liquid crystal panel. The microlenses are generally formed on a microlens substrate provided in the liquid crystal panel.
FIG. 9 is a schematic longitudinal-sectional view showing the configuration of a microlein; substrate used in the known liquid crystal panel.
As show n in the drawing, a microlens substrate 900 includes a glass substrate 902 provided with a number of concavities 903, and a glass layer 908 bonded to the glass substrate 902 via a resin layer 909 on a surface of the glass substrate 902 provided with the concavities 903. Microlenses 904 are formed in the resin layer 909 with a resin filling the concavities 903.
The microlens substrate 900 is formed in a process such that the resin before curing is supplied onto the glass substrate 902, the glass layer 908 is bonded to the glass substrate 902 via the resin, and the resin layer 909 is formed by curing the resin.
When the glass layer 908 is bonded to the glass substrate 902 in manufacturing the microlens substrate 900, the thickness of the resin layer 909 has been regulated by controlling the force and the time for pressing the glass layer 908 onto the glass substrate 902.
However, limitation of improving accuracy in regulating the thickness of the resin layer 909 by such a method has been noticed.
Accordingly, an object of the present invention is to provide a method for manufacturing a microlens substrate, and to provide a microlens substrate, an opposing substrate for a liquid crystal panel, a liquid crystal panel, and a projection display apparatus, in which the thickness of a resin layer can be regulated with high accuracy.
To the end, according to the present invention, a method for manufacturing a microlens substrate comprises the steps of supplying a resin onto a first substrate provided thereon with a plurality of concavities; bonding the first substrate to a second substrate via the resin; and forming microlenses with the resin filling the concavities. The first substrate and the second substrate are bonded to each other by providing a resin including a spacer outside a region in which the concavities are formed.
The resin forming the microlenses and the resin including the spacer preferably include the same material. The spacer may include particles or globular particles. The resin including the spacer may contain 1 to 50 percent by weight of the spacer. The second substrate may be made of glass.
A microlens substrate comprises a first substrate provided thereon with a plurality of concavities; a resin layer provided so as to cover the concavities, and microlenses formed with a resin filling the concavities. A spacer for regulating the thickness of the resin layer is provided outside an effective lens-region including the microlenses.
The spacer is preferably provided in the vicinity of an edge of the microlens substrate. The microlens substrate may be substantially quadrilateral and the spacer may be provided in the vicinity of at least three sides of the quadrilateral. The spacer may include particles or globular particles. The standard deviation of particle-size distribution of the spacer may be not greater than 20 percent of an average particle size of the spacer. The density of the spacer may be 0.5 to 2.0 g/cm3. A value xcfx811/xcfx812 may be 0.6 to 1.4, in which xcfx811 denotes the density (g/cm3) of the spacer and xcfx812 denotes the density (g/cm3) of the resin forming the resin layer. An outer layer may be provided on the resin layer. The outer layer may be made of glass or ceramics.